Book Image

Mastering PLC Programming

By : Mason White
Book Image

Mastering PLC Programming

By: Mason White

Overview of this book

Object-oriented programming (OOP) is a new feature of PLC programming that has taken the automation world by storm. This book provides you with the necessary skills to succeed in the modern automation programming environment. The book is designed in a way to take you through advanced topics such as OOP design, SOLID programming, the software development lifecycle (SDLC), library design, HMI development, general software engineering practices, and more. To hone your programming skills, each chapter has a simulated real-world project that’ll enable you to apply the skills you’ve learned. In all, this book not only covers complex PLC programming topics, but it also removes the financial barrier that comes with most books as all examples utilize free software. This means that to follow along, you DO NOT need to purchase any PLC hardware or software. By the end of this PLC book, you will have what it takes to create long-lasting codebases for any modern automation project.
Table of Contents (25 chapters)
1
Part 1 – An Introduction to Advanced PLC Programming
6
Part 2 – Modularity and Objects
10
Part 3 – Software Engineering for PLCs
14
Part 4 – HMIs and Alarms
19
Part 5 – Final Project and Thoughts

Understanding recursion and the THIS keyword

Recursion is a looping concept that isn’t used much in today’s world. However, it is a concept that often pops up in interviews and is something that all software engineers need to understand. In a nutshell, recursion is where a method calls itself. Recursion is a valid concept and is an important concept to know; however, for many applications, some type of loop will be more appropriate.

If you do opt to use recursion, exercise great caution. Recursion is generally considered resource-heavy, and in the automation world, where many PLCs have traditionally limited computing resources compared to full-fledged computers, it can consume precious resources.

Recursion is also somewhat dangerous as it is easy to create what is known as an infinite recursive loop. These loops are recursive loops that continuously call themselves. Many modern compilers do check for this and will usually throw a compile error before the code is...